Seroquel - How long does it take for seroquel to take effect?

Hi, MarySue! Some people begin feeling some positive effects at around four weeks, but it may take as long as 6-8 weeks to reach maximum therapeutic blood levels. You should however feel some mild side effects such as drowsiness and headache almost right away. They are generally transient, lasting only a few days to a few weeks,
Best wishes, WCV

Good answer from Wildcat; But if they are giving this to you for sleep many people say it works much sooner.BUT for all the other things it can do it's all on WildcatVets post. Chuck1957